Fix over/underflow with numpy.int16 (#36)

* Fix under/overflow with numpy int16
* v3.7.2

plotille/_util.py

@@ -50,6 +50,13 @@ def roundeven(x):
     return x_r
 
 
+def _numpy_to_native(x):
+    # cf. https://numpy.org/doc/stable/reference/generated/numpy.ndarray.item.html
+    if ('<class \'numpy.' in str(type(x)) or '<type \'numpy.' in str(type(x))) and callable(getattr(x, 'item')):
+        return x.item()
+    return x
+
+
 def hist(X, bins):
     """Create histogram similar to `numpy.hist()`
 
@@ -69,6 +76,10 @@ def hist(X, bins):
     if xmin == xmax:
         xmin -= 0.5
         xmax += 0.5
+
+    xmin = _numpy_to_native(xmin)
+    xmax = _numpy_to_native(xmax)
+
     delta = xmax - xmin
     is_datetime = False
     if isinstance(delta, timedelta):
@@ -79,7 +90,8 @@ def hist(X, bins):
 
     y = [0] * bins
     for x in X:
-        delta = (x - xmin)
+        x_ = _numpy_to_native(x)
+        delta = (x_ - xmin)
         if isinstance(delta, timedelta):
             delta = timestamp(delta)
         x_idx = min(bins - 1, int(delta // xwidth))

pyproject.toml

@@ -1,7 +1,7 @@
 [tool.poetry]
 
 name = "plotille"
-version = "3.7.1"
+version = "3.7.2"
 description = "Plot in the terminal using braille dots."
 authors = ["Tammo Ippen <tammo.ippen@posteo.de>"]
 license = "MIT"

tests/test_util.py

@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import numpy as np
+
+from plotille._util import hist
+
+
+def test_hist_neg_idx():
+    x = np.random.randint(-32767, 32767, 100, dtype=np.int16)
+
+    expect = np.histogram(x, bins=8)
+    actual = hist(x, bins=8)
+
+    assert list(expect[0]) == actual[0]  # counts
+    assert list(expect[1]) == actual[1]  # bins